This invention relates to matrix printing apparatus, and more particularly relates to matrix printing apparatus which is specifically adapted for high speed printing of tickets formed from a continuous roll of paper stock.
Customarily, matrix printer apparatus is comprised of a print head having print wires arranged in a column and mounted on a movable carriage to advance along each line of a print medium in forming individual characters, following which the print medium is indexed to the next line as the print head is returned to the margin for printing each next line in succession. The number of print wires is selected according to the height of the characters formed so that as the head is advanced across the paper each character is formed by selectively activating certain of the print wires at closely spaced incremental positions to individually form each character followed by spacing and proceeding to the next character. In the high speed printing of information on a relatively narrow print medium, or in other words, where the margins are relatively close to one another, considerable savings in motion, time and energy may be realized by providing a print head with a sufficient number of print wires to traverse the entire width of the print medium and thereby obviate movement of the print head back and forth across each line to be printed; instead, characters or designs may be formed on the print medium by activating different selected print wires in each line or row as the print medium is advanced in a direction transversely of the row of print wires. Printing in this manner may be best exemplified by reference to its use in the printing of betting tickets for various wagering operations or games of chance in which it is desirable that the tickets be readable both by the customer and by special code readers so that the information printed on each ticket may be verified instantaneously prior to turning over the ticket to the customer.
In order to print tickets in the most rapid, efficient manner, it is highly desirable that the ticket or paper stock be advanced across the print head from a continuous roll; and after each ticket is printed, that means be provided for cutting and ejecting the ticket without interrupting continuous advancement of the paper stock in printing each next ticket in succession. In advancing the paper from the continuous roll, it is necessary to overcome the effects of inertia or drag which tends to increase as the supply roll is reduced in size or diameter. This is especially critical where the stock is to be frictionally advanced at a continuous rate of speed so as to assure uniform spacing between the closely spaced lines of print in forming each character as well as to minimize power requirements both for the paper advancing mechanism and the print wires.